热辅助纳秒脉冲激光抛光试验研究

Experiment on thermally assisted nanosecond pulsed laser polishing

为提升纳秒脉冲激光抛光加工的质量及效率,对基于热辅助的纳秒脉冲激光抛光开展了试验研究。定性分析了工件热辅助对激光抛光的热影响;以通过增材制造的Ti-6Al-4V原始表面为试验对象,利用共焦显微镜、扫描电子显微镜和能谱仪,对在不同激光能量密度及补偿温度下抛光后的表面及横截面进行了分析,揭示了工件补偿温度、激光能量及表面加工质量间的关系;进一步利用维氏硬度计测量了其维氏硬度,分析了重结晶层及熔融层对表面硬度的影响规律。研究结果表明:在较高的补偿温度下,热辅助激光抛光获得与无热辅助条件下相似的表面粗糙度只需较低的能量密度;这也表明了在相同的激光输出功率下,热辅助激光抛光补偿温度越高,加工速度越高,其抛光效率也会得到有效提升。

Experimental research on nanosecond pulsed laser polishing under thermal assistance was carried out aiming at improving its quality and efficiency.First,on the basis of qualitative analysis of the effect of workpiece thermal assistance on laser polishing,the original surface of additively manufactured Ti-6Al-4V was used as the test object,and the confocal microscope,scanning electron microscope and energy spectrometer were used to analyze the polished surface and cross-section under different energy density and compensation temperature.Then the relationship between the compensation temperature of the workpiece,the laser energy and the surface processing quality was revealed.Furthermore,Vickers hardness tester was applied to measure its hardness,and the influence of the recrystallized layer;the molten layer on the surface quality was also analyzed.The results indicate that at a higher compensation temperature,heat-assisted laser polishing can obtain a similar surface roughness as under the no heat-assisted conditions with a lower energy density.It also shows that under the same laser output power,the higher the compensation temperature,the higher the scanning speed of thermally assisted laser polishing can be,so as to effectively improve the efficiency of nanosecond pulse laser polishing.